The present disclosure generally relates to differential motion sensing and, more particularly, to slat differential motion sensors.
Differential motion sensors can be used to detect displacement of adjacent objects and/or components. Slat differential motion sensors, for example, can be used to detect displacements and skews of aircraft control surfaces, such as slats or flaps on aircraft wings. The displacement of the slats may be caused, for example, by an actuator disconnection from the surface it drives.
Conventional slat differential motion sensors typically employ two hinged arms configured to move independent from one another. The arms are connected by an electromechanical fuse. The slat differential motion sensor is typically mounted to a first panel, while a striker pin is connected to a second panel. A system controller is provided to monitor continuity at the fuse and the status of the sensor. When abnormal differential motion occurs, the fuse is loaded in tension (i.e., realizes a tensile force) and fractures the fuse, annunciating the failure to the system controller. Conventional slat differential motion sensors, however, are affected by the spanwise motion (i.e., motion parallel to the span of an aircraft wing) of the panels. Spanwise motion results in significant variation of forces acting upon the fuse which has to be designed to assure functional repeatability of skew detection without nuisance signaling to the system controller. Greater spanwise motion, for example, results in a lower pin force but a less sensitive sensor.